Field of the Invention
The invention relates to a textile machine, preferably an open-end spinning machine, that processes sliver from sliver cans, including an automatic can changer for replacing cans that have become empty with filled cans, a device for monitoring the sliver can contents and for recognizing a break in the sliver if the sliver cans are still partly full, and a number of work stations disposed side by side, the sliver cans being disposed in at least two rows one behind the other, for supplying the side-by-side work stations.
In open-end spinning machines in which the sliver is delivered to the spinning stations from cans, as a rule the cans have larger dimensions than the width of a corresponding spinning station. That means that in order to utilize the space under the spinning stations, the cans typically have to be disposed in at least two rows, one behind the other. The association or assignment of the cans to the various spinning stations is defined precisely. Once set, the association of sliver cans must be strictly adhered to, especially if an automatic change of sliver cans at spinning machines is provided, otherwise proper can changing is impossible. As a rule, the slivers of the front cans and the slivers of the rear cans are delivered to the side-by-side spinning stations in alternation. Thus, as seen by looking toward the work station, the can associated with every other work station is disposed behind the cans of the adjacent work stations. The cans may be somewhat staggered behind one another, so that the rear cans are fitted into a gap between two front cans, in a super-tight packing. However, the cans may also each be disposed directly behind one another so that, for instance, two cans are located at the boundary of each of the abutting, associated spinning stations.
In order to enable initiation of an automatic can change, a sliver monitor is disposed on each spinning unit in order to issue a signal whenever there is no longer any sliver. A sliver counter is also provided, which counts backward as sliver is drawn off, for a given length of sliver. A can change is initiated automatically only when the sliver counter has run out and the sliver monitor signals an absence of sliver.
If a sliver should tear as it runs out of the can, only the sliver monitor issues a signal. The sliver counter has not yet run out, and therefore no can change is required. In that case, the operator of the machine has to intervene and put the sliver back in place.
For instance, if the sliver from a rear can has broken, then the front can first has to be moved out of the way, in order to gain access to the rear can to look for the sliver. The sliver is then picked up and introduced into the corresponding spinning station. Next, the cans have to be pushed back to their previous place. However, when the cans are returned to their previous place, the operator may transpose the positions of the cans. The can that at first was at the back may be pulled frontward, while the front can is pushed backward. The contents of the cans, each of which is ascertained by the sliver counters, will then no longer match the contents of the cans actually associated with them after the transposition has taken place. It is thus possible for the sliver counter at one spinning station to have run out while sliver is still present, since the can still contains enough sliver. On the other hand, a situation may ensue wherein the sliver has run out completely in the can while the sliver counter has not yet run down to zero. In both cases defects occur, which unnecessarily have to be taken care of by the operators. It is also possible for a can that is still sufficiently well filled with sliver to be replaced with a full can.